Ornimys proavus
The earliest known theropodent known is Ornimys proavus'', living 75 million years ago. About as large as a rabbit, it was likely omnivorous, feeding on seeds and also small insects. Its descendants would later specialize from that broad diet onto two very different diets - vegetation for the bronkjirds, and flesh for the vultrats - with anomolospectrodonts and faeries remaining more broadly omnivorous'' .'' The '''theropodents' are the most successful mammal clade on Pluvimundus. Originating in the open grasslands of the northern hemisphere, they evolved as small, gerbil-like omnivores 75 million years ago '''and have in the eons since spread across the entire planet, from pole to pole. Named in portmanteau of rodent and theropod, they strongly share anatomical traits with both Earth clades. Like the theropod dinosaurs, they are bipedal, usually with horizontally-carried bodies which balance their front ends with a long tail, though the early-divergent '''anomolospectrodonts '''have a more upright carriage. Like all hematotherms, their bodies utilize air sacs that enter the bones and tissues, like Earth birds, and allow them a very efficient respiration as well as a lighter body weight at large size. Also like birds, they are ancestrally digitigrade, with a highly elongated metatarsus that raises the ankle high off the ground and makes them fast runners, a locomotion they developed from an earlier hopping gait in their smaller ancestors. Their skulls are strikingly convergent to rodents; though the resemblance is most obvious in early fossil forms, all theropodents have highly derived dentition originally adapted to gnaw seeds', with a pair of upper and lower incisors being very prominent, the canines absent, and a diastema - a gap in the teeth - often present between the incisors and molars. The two major megafaunal theropodents have either adapted their incisors alternately into a cropping beak-like structure under the lips, in the herbivorous' bronkjirds', or into fearsome flesh-cutting tools in the case of the carnivorous '''vultrats', which have the most specialized of all teeth, with each incisor having a sharp slicing blades on the outer edge and a blunter, inner cusp. Theropodents are almost all social animals, and also include some of the most intelligent native wildlife, with the vultrats in particular having highly developed social structures and cognitive abilities. Many vultrats are cooperative hunters and exhibit prolonged parental care. Bronkjirds most often live in large''' herds, numbering into the millions in some migratory plains species. DNA suggests the two major lineages split from one another around 50 million years ago', though transitional forms are unknown in the fossil record. The ancestor is presumed to be an omnivore, intermediate between modern clades, and to have originated along what is today the peninsular landmass known as the Downward Passage in South Andromere, which at the time connected to Aenvarna via a land bridge. Those which would give rise to the vultrats moved north and evolved there into carnivores, while the ancestors of bronkjirds moved south and became more specialized to feed on plants on the southern continent of Aenvarna. Today there are no bronkjirds outside Aenvarna, but vultrats have reached the south in the form of sea-going, marine species known as '''foons.' Several other clades of theropodents are also found on Pluvimundus, including the sea rabbits - a group of semi-aquatic, secondary quadrupeds found across the shallow southern coasts; the faeries of Andromere, which are a young clade of seed-eating, flying animals that very strongly resemble squirrels; and anomolospectrodonts, which are highly derived, arboreal mammals with many bird- and primate-like traits, found in the primeval forests of Southwest Andromere, across Servallia and the Downward Passage. There are no living species considered a close analog to the common ancestor of the clade,' but one tentative theropodent ancestor is known in the fossil record'; originating from Central Andromere 75 million years ago, the two known fossils of Ornimys proavus, one of which is a complete skull and vertebrae without a body and the other a well-articulated hindquarters and isolated ribs with no head or forelimbs, shows a rabbit-sized creature with a long tail, a rat-like skull and very long legs; whether it was already adapted to run, or if it was a hopper like a kangaroo, is not yet established. Category:Fandom Category:Prehistoric